To correct an instant target motion to enhance dynamic accuracy by compensating the influence of an inertia force caused by bending operation of joints of a mid-portion of each leg body, the influence which is not considered in the instant target motion generated by an instant gait generation means.

From a standing upright state of a robot 1, the joints 16R and 16L of the mid-portion of each leg body 2 are bent to reduce the length of a line segment connecting a predetermined point in the vicinity of the front end of each leg body 2, and a predetermined point in the vicinity of a connection portion between the leg body 2 and an upper body 3, thereby generating a gait for protruding the joints 16R and 16L in a direction intersecting with the line segment. At that time, the position of the connection portion between the upper body 3 and each leg body 2 is displaced from the position of the connection portion determined by the instant target motion in the opposite direction of the protrusion direction of the joints 16R and 16L of the mid-portion of the leg body 2. The instant target motion is then corrected so that the position of the upper end with respect to the lower end of the upper body 3 is displaced from the position of the upper end with respect to the lower end of the upper body 3 determined by the instant target motion in substantially the same direction as the protrusion direction of the joints 16R and 16L of the mid-portion of the leg body 2.